• 关键词：藻华暴发  空间分异  赋存形态  潜在生态风险

• 基金项目：国家水体污染控制与治理科技重大专项（ No.2017ZX07603-003）

• 王育来
• 安徽工业大学能源与环境学院，马鞍山 243002

• 刘馨
• 安徽工业大学能源与环境学院，马鞍山 243002

• 高越
• 安徽工业大学能源与环境学院，马鞍山 243002

• 杨长明
• 同济大学，长江水环境教育部重点实验室，上海 200092

• 汪世旭
• 安徽工业大学能源与环境学院，马鞍山 243002

• 摘要：为探究湖泊富营养化过程对沉积物中重金属空间分异及生态风险的影响，本研究以大型浅水湖泊—巢湖为研究对象，剖析了藻类暴发前、后巢湖表层沉积物中典型重/类金属（Cr、Ni、Cu、As、Cd、Pb）含量及其赋存形态的空间分布特征，并采用次生相与原生相比值、潜在生态风险指数法评估了沉积物重/类金属的污染程度与生态风险的变化规律. 结果表明：①藻类暴发前6种重/类金属含量空间分布特征均表现为西部湖区显著高于中部和东部湖区（p< 0.05，p< 0.01），而暴发后沉积物中重金属含量均有所增加，且空间上呈现均一化趋势；②藻类暴发前Cr、Ni、Cu、As和Pb均以残渣态为主，Cd以弱酸提取态为主；藻类暴发后6种重/类金属的残渣态相对质量分数均有所降低，可氧化态相对质量分数均有所增加；③藻类暴发后沉积物重金属综合污染程度由暴发前的中等污染程度提升为较高污染程度，且单一重金属污染程度表现出空间分布均一化的趋势；④潜在生态风险指数结果表明藻类暴发增加了沉积物重金属污染（As除外）的生态风险. 本研究阐明了藻类暴发对巢湖沉积物重金属空间分异及其生态风险的影响，可为大型浅水湖泊生态健康评估与内源污染控制提供支撑.

• Abstract：To clarify the impacts of algae bloom on the spatial differentiation and potential ecological risk of heavy metals from sediments in large shallow lake. In this study, we investigated the spatial distribution patterns of Cr, Ni, Cu, As, Cd and Pb from surface sediments in the Chaohu Lake, and analyzed their fractions by three-step extraction method. In addition, we also evaluated the degrees of heavy metal contamination and their potential ecological risk by the ratio of secondary phase and primary phase (RSP) and potential ecological risk index (RI). The results showed that: ①The contents of the six heavy metals in western region were higher than those of central and eastern region of the lake before algae bloom (p< 0.05，p< 0.01). However, the contents of Cr, Ni, Cu, As and Pb in sediment increased after algae bloom, and no significant difference was observed between different regions. ②The residual fraction of Cr, Ni, Cu, As and Pb dominated in sediment while acid soluble fraction was predominant for Cd before algae bloom. We found that the relative proportions of the six heavy metal residual fractions decreased and the oxidized ones increased after algae bloom. ③ The degrees of heavy metal contamination changed to moderate pollution level after algae bloom, and the pollution degree of each metal exhibited similar trend. ④The potential ecological risk of Cr, Ni, Cu, Cd and Pb in sediment increased after algal bloom. The present study elucidated the impacts of algae blooms on the spatial variation patterns and their ecological risk of heavy metals from sediments in the Chaohu Lake, and these results would provide theoretical and practical supports for ecological health assessments and internal pollution control for large shallow lakes.

• Key words：algae bloom  spatial differentiation  fractions of heavy metals  potential ecological risk

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